China International Capital Corporation forecasted that petrol and diesel retail prices will be raised by 500 yuan per ton in the near future, up 8.8 percent and 10 percent, respectively, as the international oil price began to climb up recently.

Jiang Jiemin, board chairman of PetroChina, also expressed that China's product oil retail price may be escalated by 500 yuan per ton in accordance with the new product oil pricing mechanism.

The price hike expectation drove up the sales of product oil. And China's net import of product oil dropped 31 percent in April, resulting in a fall in product oil stock. Accordingly, China's refineries increased crude oil processing volume.

China's two oil giants PetroChina and Sinopec posted 15 percent drop in their product oil stock in April, and their sales increased 5.2 percent in March.

According to C1 Energy, an energy information portal website, PetroChina plans to process 9.85 million tons of crude oil in May, up 550,000 tons or 5.86 percent from April.

Data from the National Bureau of Statistics showed that China's crude oil processing volume increased 6 percent to 29.4271 million tons in April, compared to the 0.7 percent increase in March.